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Posted By: phadob29 Voice T1 over ethernet via Cisco router - 09/14/07 07:18 AM
Here is the question:
I have a remote location where I want to bring a T1 to. I had established a long range wireless connection over the 3.5 mile distance. This connection is an ethernet connection, leaving site A from a Cisco 1841 router and arriving on the other end to a Cisco 1841. I use the LAN port of this cisco to carry my LAN over to the other site, but I also got a WIC-T1-CSU/DSU card in there. I'm hoping I can plug in a line side T1 into this T1 slot, and somehow carry it over to Site B and get it out on the other end on the WIC-T1 slot of the other Cisco 1841, and plug that into a Channel bank, and receive 24 dial-tones. Can this be done the way I described?
Thanks. Peter
It can't be done with the equipment you have on hand. Cisco has other cards and routers that can do it but would have to look it up.
Posted By: Kumba Re: Voice T1 over ethernet via Cisco router - 09/15/07 01:44 PM
You can take the T1 to data before the cisco, and then break it out after the cisco. You'd be doing a single-hop VoIP basically. Plenty of options for that.

I've done that before with IAX and Asterisk in order to artificially extend phone lines.

You trying to extend an RBS/CAS T1 or a PRI T1? And what size Wireless pipe?
Posted By: phadob29 Re: Voice T1 over ethernet via Cisco router - 09/15/07 09:14 PM
Quote
Originally posted by Kumba:
You trying to extend an RBS/CAS T1 or a PRI T1? And what size Wireless pipe?
It's an RBS T1 and I'm getting 42mbps on the wireless. Any data you could provide me with would be much appreciated.
Posted By: Kumba Re: Voice T1 over ethernet via Cisco router - 09/15/07 10:04 PM
Hmmm... one method is to look into a T1 Media gateways. You would need to configure them to be immediate meaning when one goes off-hook, it connects to the other immediately and doesn't wait/read DTMF. Mediatrix or Multitech make such things but they get rather pricey for a T1.

I'm sure there are IP phone systems that can simulate this by passing a channel to an ATA on the other end. Someone else here could better fill you in on those kinds of options.

I can do it with Asterisk which is a software-based PBX that runs on Linux. Easiest way is to have the asterisk box at your remote end handle the dialtone and just go out over the link when a valid phone # is dialed. This gives you the option of having a terrestrial-based pots line for fallback and e911 if you want. 24 T1 lines would consume 1.544mbps + 32kb or overhead and include an adaptive jitter buffer so that faxing would work right. Note that this is with asterisk and a protocol called IAX.

You can go through the find an installer link and call some of the people from tampa and see what kind of products they have to do this as well.

If you want more info on asterisk just send me a PM. Thanks.
Posted By: phadob29 Re: Voice T1 over ethernet via Cisco router - 09/15/07 10:29 PM
We have an NEC PBX with an RBS T1 and we are thinking about using T1 to Ethernet converter before and after the Ciscos. Do you think that will work? Thanks a lot.
Posted By: Kumba Re: Voice T1 over ethernet via Cisco router - 09/15/07 10:38 PM
Yeah... as long as the converter/gateway is designed for a Voice T1 then you should be good to go.

The radio latency combined with the IP latency might play havoc with echo and fax but it should work in theory.
Posted By: phadob29 Re: Voice T1 over ethernet via Cisco router - 09/18/07 10:07 AM
I have the following plan:

RADirect IPMux411 to convert the T1 into Ethernet, feed that into the Router, and on the other side, use the same IPMux to extract T1 out of the Ethernet packets. Sounds workable?
Posted By: Kumba Re: Voice T1 over ethernet via Cisco router - 09/18/07 10:25 AM
Sounds like a good workable plan... I assume the wireless is essentially a single-hop point-to-point link right? Or is it part of a wifi network where you have a bunch of other access points on it?

If there is a lot of wireless traffic from other access points it could cause issues with collisions and voice clipping, but it would need to be a fairly busy network for that to have much of an effect.

Also not a bad idea to give your T1 data a higher QoS then everything else to make sure that bandwidth is never stolen from it.
Posted By: Kumba Re: Voice T1 over ethernet via Cisco router - 09/18/07 01:51 PM
I am sitting here now trying to google that device you mentioned in order to get a better look at it's capabilities. After finding something like it I think that it may not work for wifi. When I made the original suggestion to you for a T1 to IP gateway I was assuming that you would look for a SIP gateway setup. This is where I think I may have led you wrong.

If it uses what is called TDMoE then you will not want to use it with a wifi connection. It's more like what you would use for a dedicated point-to-point ethernet set-up with a cross-over cable or switches. This is a layer-2 style device meaning it will need dedicated links because of the large amount of packets that it will generate. It does not attempt to resample or consolidate the TDM packets together into a larger IP packet like SIP does. It acts exactly like TDM does and any network/wifi collisions or packet-resends result in a lost audio frame. It will also be blasting packets at a steady 1khz rate.

A quick google got me a device from RADirect called the IP-mux 11 that uses what it calls "TDMoIP" which is leading me to believe it's the same thing (different name) as I mentioned above. Please provide me a link or a better description to what you intend to use as the description you posted did not come up in google.

TDMoE (or TDMoIP) is a good way to get a high-number of channels through a single link but it is very hard on the network from the standpoint that you cant do any packet resends or have collisions. They very design of it is just TDM transported on top of IP, and similar to TDM, it requires a dedicated point to point data path.
Posted By: phadob29 Re: Voice T1 over ethernet via Cisco router - 09/19/07 06:57 AM
Thanks for looking it over. What you found is RADirect's IP-Mux 11. I found the same thing, but while 11 is doing only one T1, the IP-Mux41 will do up to four T1/E1-s. And that's what I need as I actually (if I can make it work) will send a T1 and an E1 over the wireless link.
And yes, this wireless link is a single ptp hop at 40mbps, no mesh network here.

Peter
Posted By: Kumba Re: Voice T1 over ethernet via Cisco router - 09/19/07 07:25 AM
Well I cant guarantee how stable it will be with wifi. It will work for what you want to do though.

If this solution isn't stable or is lacking features you want i'm in the greater Tampa Bay area and can help you find something better or develop a custom Asterisk solution for ya.

Either way, keep us posted, i'm sure others are interested to see how well it works out.
Cisco gateways can do what you want, but not an 1800.

There are radio systems with built in T1 ports that will do what you want.

Otherwise, use the RAD, that will work fine too.
Tradeoff between delay (latency) and echo, but you'll see that when you configure the RAD. It's pretty straightforward.

I've done all three of these solutions.
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